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Biology Chapter 1

Terms in this set (80)

MAIN IDEA- Biology is the scientific study of life. All livings things display a shared set of characteristics
. Nonliving matter never display all of these characteristics of life simultaneously
Biology
the scientific study of life
Important Questions: What is life?
What is the difference between living and non-living organisms?
Properties of Life
Reproduction, Growth and Development, Energy Use, Order, Cells, Response to the Environment, Evolution
Reproduction
all organisms reproduce their own kind
Reproduction ex.
Elephants only produce elephants
Growth and Development
o information carried by genes controls the pattern of growth in all organisms.
Growth and Development ex.
. All African elephants grow tusks as they age
Energy Use
every organism takes in energy, converts it to useful forms, and expel energy
Energy Use ex.
Elephant eats plants, uses the energy to move, and releases the energy as heat
Order
each living thing has a complex but well-organized structure
Order ex.
Elephant eye
Cells
all living organisms consist of cells
Cells ex.
Some living organism has one cell but others have trillions
Response to the Environment
All organisms respond to changes in the environment. Many of these responses help to keep an organism's internal environment within narrow limits even when the external limits even when the external environment changes
Response to the Environment ex.
Elephants responds to the heat of day by taking a bath, which helps keep its body temperature steady
Evolution
o Individuals with traits that help them survive and reproduce pass the genes for those traits to offspring. Over many generations, such adaptations drive the evolution of populations.
? Which properties of life does a car display? Which does it not?
A car uses energy, is ordered and responds to the environment. A car does not reproduce, grow and develop, evolve, or is made of cells
Is A Virus Alive?
NO!
Virus
does not display all of the properties of life
Virus properties
While nonliving matter may display some of life's properties (a virus has order for example), never displays all of life's properties simultaneously
? Which level of life's organization is the smallest one that can be considered alive?
the cell is the smallest unit that is capable displaying all of life's properties
Virus ex.
A virus is not composed of cells, and cannot reproduce on its own
MAIN IDEA- Life can be studied on a hierarchy of levels from the very large to the very small.
Biologists study life at all of these levels
The Levels of Biological Organization
biosphere, ecosystems, communities, populations, organisms, organs and organ systems, tissues, cells, organelles, molecules
Biosphere
consists of all life on Earth and all of the environments that support life, from the deepest oceans to high in the atmosphere
Ecosystem
includes all the living organisms in one particular area (African savannah) components that affect life, such as soil, air, and sunlight.
Community
consists of all the interacting populations of organisms occupying an ecosystem. This community includes plants, animals, and even microscopic organisms
Population
a group of interacting individuals of one species such as the African savanna dear
Organism
an individual living being, such a Tiger
Organ System
a group of organs that work together to form a vital body function. For example, the circulator system of the tiger transport need materials and wastes
Organ
consists of multiple tissues that cooperate to perform a specific task. The tigers' heart, for example pumps blood through the circulatory system
Tissue
an integrated group of similar cells that work together to perform a specific function. This microscope image shows a section of cardiac epithelial tissue which lines the heart, allowing blood to flow freely over the surface
Cell
the fundamental unit of life. Nothing smaller than a cell is capable of having all of life's properties. Some organisms (such as a bacterium) have one cell; others (like an elephant) have trillions
Organelle
a component of the cell that performs a specific function. An epithelial cell's nucleus, for example, houses the DNA
Molecule
A group of atoms bonded together. Here is a computer-generated image of DNA, a molecule essential to all life on Earth. Each atom is represented as a ball
Atom
the fundamental unit of matter; it is the smallest unit of an element capable of displaying the properties of that element. Atoms themselves are made up of even smaller units called subatomic particles
? Which level of life's organization is the smallest one that can be considered alive?
the cell is the smallest unit that is capable displaying all of life's properties
Process of Science
MAIN IDEA- Scientific investigations always start with observations, which may lead to hypotheses and experiments that provide data on the validity of the hypotheses
Careful observations and experimentation allow scientists to investigate hypotheses and develop theories
Biologists use the process of science to study
life
Scientific Method
a series of steps that, if followed, may provide insight about the natural world.
Science
begins with observing the world
Discovery science
refers to learning about the natural world by making verifiable observations, taking measurements and gathering data. The data may prompt questions and guide further scientific exploration.Ex. You might sample many cookies and notice the differences between them. Once you've gathered sufficient data, you may end your investigation at this stage or your observations may lead to questions that you'd like to test
Science in Action
Represents possible path of inquiry
Hypothesis
- a proposed explanation for an observation. A valid hypothesis must be testable, and the results will either support or refute the hypothesis. For example, the endosymbiotic hypothesis proposes that some cellular components (such as chloroplasts and mitochondrion visible in the plant cell) were once free-living organisms that were long ago incorporated into a larger cell.
Theory
a well-sustained explanation that is much broader in scope than a hypothesis. It is much more comprehensive, it has not been shown to be false, and it already explains a great many observations.
For example, the Cell Theory states that every living organism consists of cells that arose from preexisting cells.
Theories are supported by a large and growing body of evidence and can be used to devise specific hypotheses to be tested
? You ask a friend "Where's the cat?" Your friend replies "I don't know, but my theory is that she escaped outside. "How would you reword your friend's reply to make it more scientific?
change "theory" to "hypothesis" since the latter word more properly expresses the proposed explanation
CONTROLLED STUDIES
MAIN IDEA- To most clearly investigate hypotheses, scientists try to change just one variable per experiment
An independent variable is one that is changed to see tis effect on a dependent variable. Performing experiments blind can reduce bias
Controlled experiment
a test is run multiple times with one variable changing-and ideally, all other variables held constant.o Used to investigate a hypothesis.
Allows scientist to draw conclusions about the effect of the one variable that did change. Ex. If you were baking cookies, you could try changing one ingredient- the type of flour you use-while keeping all other variables the same.
You would then be confident that any changes to the cookies were due to that change
Independent Versus Dependent Variables
In experiment above the type of flour was used to see if it had an effect on cookie thickness
Independent variable
o what is being manipulated as a potential cause (type of flour)
One independent variable at a time
Dependent variable
the response, output, or effect under investigation (cookie height)
Control group
one that is used toe stablish a baseline for an experiment (cookies baked according to standardized recipe.By comparing the cookies that result from each change in the recipe to the control group. The experimenter can be confident that any observed differences are due to one change.
Blind experiment
some information about the experiment is withheld from participants.
Single-blind experiment- a scientific experiment in which some information is withheld from the test subject.Ex. To evaluate the effect of flour on your cookies, you could ask a friend to rate each recipe. You label it A or B and your friend is blind to the type of flour. Removes bias
Double-blind experiment
an experiment in which neither the participant nor the experimenter knows which group is which neither the participant nor the experimenter knows which group is which - ex. You did not know which type of flour was used in group a and group b
Placebo
a medically ineffective treatment that allows the placebo group to serve as a control for the real drug
The "gold standard" for a medical trial is to be run as
"double- blind placebo-controlled studies" meaning neither the patients nor doctors know which patients receives the real or placebo
? I try feeding my dog the same amount of dog food with and without added water. What are my independent and dependent variable?
The independent variable is the presence of absence of added water. The dependent variable is how much mu dog enjoys the food
Pseudoscience
any field of study that is falsely presented as having scientific basis
-a pseudoscience study may make unprovable claims or it may be based on anecdotal evidence (an assertion based on a single or a few examples that do not support a generalized conclusion
Examples of Pseudoscience
Fortune telling is not repeatable; different results for the same starting data.
-Pseudoscientists often use scientific- seeming but useless gadgetry.
- Predicting personality traits based on skull measurements does not stand up to independent review.
-Claims of ESP have never been demonstrated in a controlled scientific setting
RELIABLITY OF SOURCES

MAIN IDEA-Biology is limited to the study of life via recognized scientific approaches
Through peer review, outside authorities can help verify the validity of scientific results. Other ways of thinking, such as pseudoscience are not considered part of biology
Peer review
the evolution of work by impartial, qualified, often anonymous experts who are often not involved in that work
Gold standard for valid scientific work included reliable scientific information that can be recognized up to date drawing from known sources of information
having been authorized by a reputable expert, and being free of bias
Primary source
original material presented for the first time by the person(s) who performed the research
-ex. Include peer-reviewed journal articles, technical reports, and dissertations.
Secondary source
- a description or review of a primary sources often containing commentary
-ex. Include summary websites such as Wikipedia, WebMD, and many government websites; and books, newspapers, encyclopedias, and magazine articles
? You click a Facebook link that brings you to a page that describes a recent scientific breakthrough. Is that page a primary or secondary source?
Assuming that page is written by someone describing the work (and not the people who actually performed the work), then it is a secondary source.
Data
pieces of information that result from measurements. Nearly every scientific investigation produces data
Scientists use tables to collect, organize, and share data
Scientific table
efficient way to present a lot of data in a small amount of space
Graphs
means of displaying data visually, and can be used to summarize information
Line graph
often used to display data that changes continuously. Plot individual pieces of data then connect them
Bar graph
often used to compare categories of data
Error bars
may be used to represent the range of values that fall within a 95% confidence interval. If the authors can say with 95% confidence that the true answer falls within the range depicted by the bar
Pie chart
used to convey percentages
? According to the table, what percentage of the total number of breast cancer diagnoses and death involve men?
About 1% of deaths are among men
EVOLUTION
MAIN IDEA- Major themes- such as evolution, the relationship of structure and function, transformations of energy and matter
the flow of information, and interconnections between elements of biological systems- unify the study of biology at all levels
o The scientific explanation for the common characteristic found throughout such diverse species is evolution
The descent with gradual modifications of ancestral species to modern-day ones.
o The theory of evolution by natural selection, first described by Charles Darwin more than 150 years ago, is the core theme that unifies all of biology.
Evolution can help us investigate and understand every aspect of life, from the tiny organisms that occupy the most remote habitats, to the diversity of species, to the stability of the global environment
STRUCTURE AND FUNCTION
Within biological systems, structure (the shape of something) and function (what it does) often provide insight into each other.
The correlation of structure and function can be seen at every level of biological organization.
For example, your lungs function to exchange gases with the environment: oxygen (O2) is brought in and carbon dioxide (CO2) is taken out
STRUCTURE AND FUNCTION
o Within biological systems, structure (the shape of something) and function (what it does) often provide insight into each other.
The correlation of structure and function can be seen at every level of biological organization.
For example, your lungs function to exchange gases with the environment: oxygen (O2) is brought in and carbon dioxide (CO2) is taken out
ENERY AND MATTER PATHWAYS
All activities of the cell require energy and matter to proceed.
Most ecosystem energy comes from sunlight that is captured by plats and other photosynthetic organisms and is used to produce sugars and other complex molecules
Within all living cells, "chemical square dance" (metabolism) occurs molecules swap chemical partners are they receive, convert, and release matter and energy.
As they do some energy is converted to heat which is then lost from the ecosystem
INFORMATION FLOW
For life's functions to proceed in an orderly manner, information must be received, transmitted, and used. Information flow is apparent at all levels of biological organization
The information in all genes in encoded in an identical chemical language of DNA common to all organisms
INTERCONNECTION
There are many interconnections with and between levels of biological systems
The study of life extends from the microscopes scale of the molecules and cells that makeup an organism to the global scale of the entire living planet
At each new level, novel properties emerge that are absent from the preceding one. These emergent properties are due to the specific arrangement and interactions of parts in an increasingly complex system.
For example, life emerges at the level of the cell; a test tube full of molecules is not alive.
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